BYPASS GP-EXHAUST 4211129 - Caterpillar

Fuel leaked or spilled onto hot surfaces or electrical components can cause a fire. To help prevent possible injury, turn the start switch off when changing fuel filters or water separator elements. Clean up fuel spills immediately.
Illustration 1 g01182169Priming the fuel system fills the fuel filters. Priming the fuel system also removes air from the fuel system. This procedure is used primarily when the engine runs out of fuel.Note: DO NOT remove the fitting in the fuel filter base in order to release air from the fuel system during periodic service of the fuel filter. Periodic removal of the fitting will result in increased wear of the threads in the fuel filter base. This can lead to fuel leakage. However, the fitting in the fuel filter base can be used to purge air from the fuel system if the engine runs out of fuel.
Loosen the fuel filter air purge plug two full turns. Unlock and operate the priming pump until fuel appears at the fitting. This procedure will require considerable strokes. Use a cloth or a container to catch the excess fuel.
Tighten the fuel filter air purge plug. Open fuel priming pump and operate the fuel priming pump until a strong pressure is felt on the fuel priming pump. Push the priming pump plunger inward. Tighten the plunger by hand, and promptly continue with the next step.
Crank the engine after pressurizing the system.
Do not crank the engine continuously for more than 30 seconds. Allow the starting motor to cool for two minutes before cranking the engine again.
If the engine will not start, allow the starting motor to cool for 2 minutes. Repeat Steps 2 and 3 in order to start the engine. Further priming may be necessary to help purge the fuel lines of air, if:
The engine starts, but runs rough.
The engine started, but continues to misfire or smoke.
Run the engine at low idle until the engine runs smoothly.